This invention relates generally to label applicators and more particularly, to a label applicator having a hot gas dispenser for applying modem adhesive backed labels to articles.
In a typical conventional label applicator, labels having one face coated with a pressure sensitive adhesive are removed, one at a time, from a carrier web or backing strip. The labels are then transferred or otherwise supplied to a label receiver or grid. Each label is releasably retained against the label receiver by vacuum pressure applied to the inner face of the label receiver and/or by pressurized air blown against the adhesive coated surface.
When an article to be labeled reaches an appropriate position at a labeling station, a blast of air is passed through passages in the label receiver. The blast of air pushes against the label and transfers the label from the label receiver to the surface of the article. This transfer may take place after moving the label receiver and the retained label adjacent the article. The pressure sensitive adhesive adheres the label to the article. Label applicators of this general type are shown in commonly assigned U.S. Pat. No. 4,255,220, issued to Kucheck et al., and U.S. Pat. No. 4,844,771, issued to Crankshaw et al.
The typical conventional label applicator as described above is satisfactory for many labeling applications and with many types and styles of labels. However, recent advances in the design and manufacturing of labels and their adhesive backings has led to major changes in the types and styles of labels used. In particular, differing labels, including newly developed security and source tags, may have different size, weight, thickness, and adhesive characteristics that are not generally compatible with the currently available label applicators. Furthermore, for applications located in an area having cooler ambient temperatures, where the product to be labeled and/or the source tags may be quite cool, these cool conditions also often have a deleterious effect on the label adhesive, causing an even greater problem of improper adhesion of the tags to the product.
In addition to adapting to the newer labels, modem label applications often require increased production demands or labeling speeds. This may be particularly true when applying labels to smaller packages which have a quick flowthrough speed. However, merely increasing the labeling speed of these prior art label applicators often results in poor production output. Specifically, labels may be improperly adhered to the surface of the article because at the increased production speeds, the tag tends to xe2x80x9cjetxe2x80x9d or xe2x80x9cbouncexe2x80x9d off of the product to be labeled, resulting in misplacement or even falling off of a substantial number of labels or tags. The newer contact adhesives used on these modem labels may also compound this problem.
Thus, there is a need for a label applicator which can effectively and accurately apply modem labels and do so at increased labeling speeds. There is also need for an apparatus and method which can be used alone or as a modification to existing conventional label applicators such that they are compatible with and can accurately apply these newer labels and do so at increased production speeds.
There is a need for such an apparatus to be simple to install and relatively inexpensive.
The present invention satisfies the need for a label applicator that can effectively and accurately apply modem labels to articles and do so with increased production speeds. The present invention satisfies this need by providing a label applicator having a hot gas dispenser which heats the adhesive layer on each label prior to placement on the article. This application of a hot gas against the labels, just prior to their placement on the article, softens the adhesive layer and increases their ability to adhere to the articles.
In particular, the pressure sensitive adhesive applied to most modern labels typically requires a certain minimum application pressure or force to securely adhere each label to the surface of the article. If the application force is not sufficient or is not properly applied, the label may not be properly adhered to the article. In addition, the increased labeling speed of modem applications often requires a tackier adhesive to ensure proper adhesion to the article at production speeds. Heating of the adhesive layer softens the adhesive and promotes the adhesion of the label to the article. This reduces the concern that the label has not been properly adhered.
The present invention is generally directed to a label applicator for removing a label from an elongated backing or carrier strip and for applying the label to a surface on an article. The label applicator is generally configured with an outer housing or supporting structure. A label receiver is movably mounted to the supporting structure and includes a label receiving face for releasably retaining the label. The label receiving face is adapted to transfer the label to the desired surface on the article.
A label dispenser is attached to the supporting structure and is adapted for removing at least one label from the backing strip and for transferring the label onto the label receiving face. The label dispenser includes a peeler bar having a peeler plate or peeling surface and a peeling edge over which the backing strip can be drawn. Movement of the backing strip over the peeling edge peels or otherwise removes the label from the backing strip.
A hot gas dispenser is also attached to the supporting structure and is fluidly connected with a supply of a pressurized gas such as compressed air. The hot gas dispenser is adapted for heating and directing a flow of the gas against the label as the label is transferred off of the peeler bar and onto the label receiver face.
The hot gas dispenser includes an electrical resistance heater for heating the gas. A length of tubing interconnects the heater with the supply of pressurized gas and also with a nozzle. The nozzle is adapted for discharging the heated gas against the label as the label is transferred onto the label receiving face.
In another aspect of the present invention, the label applicator of the present invention includes a peeler bar heater for heating the peeling surface. The peeler bar heater is coupled to the peeler bar and disposed adjacent and underneath the peeling surface. The heater is energized or otherwise activated when the label is passed over the peeling surface to actively transfer heat into the adhesive.
In yet another aspect of the present invention, the label applicator further includes a second gas dispenser. This second gas dispenser is attached to the supporting structure such that a flow of a pressurized second gas is also directed against the label. This flow of the second gas is used to assist in transferring the label from the label dispenser and onto the label receiving face.
The second gas dispenser is spaced apart from the peeler bar and on a side opposite to the hot gas dispenser. The second gas is directed against the upper and rear surfaces of each label as the label is transferred off of the label dispenser. The second gas dispenser includes a second nozzle which is connected with a supply of a pressurized second gas such as compressed air. The second nozzle is oriented on top of, and behind, the label as it is removed from the backing strip. This location and orientation allows the flow of the compressed air to assist in the transfer of the label onto the label receiver.
A preferred method for applying a label having an adhesive on at least one face to a surface on an article according to the principles of the present invention comprises providing a label applicator, such as the label applicator of the present invention. In particular, the method comprises the step of providing a label applicator having a label dispenser with a peeler bar and a hot gas dispenser. The label dispenser is configured for removing labels from their backing strip and for transferring the labels, one at a time, to a label receiver. The hot gas dispenser is attached to the label dispenser adjacent the peeler bar and is adapted to warm the adhesive on the label.
The method also includes the step of supplying at least one of the labels to the label dispenser. The label is typically supplied as a plurality of spaced apart labels on a backing strip as previously described. The supplied label is then removed from the backing strip and dispensed from the label dispenser onto the label receiver.
The label dispenser may also be provided with a peeler bar having a peeling surface and a peeling edge as previously described and wherein the step of dispensing the label comprises slidably moving a backing strip supporting the labels across the peeling surface and over the peeling edge to sequentially remove the labels, one at a time, from the backing strip.
A flow of a hot gas is dispensed from the hot gas dispenser against the label as the label is transferred from the label dispenser to the label receiver. The heat from the hot gas softens the adhesive on the label face. After the label is transferred to the label receiver, a blast of a pressurized air is applied through the label receiver and against the label. This blast of air removes the label from the label receiver and transfers the label to the surface of the article.
In yet another aspect of the present invention, the method includes the step of heating the peeling surface. In particular, the peeling surface is heated as the backing strip is moved across the peeling surface and the label is removed. This heat is transferred through the backing strip and into the adhesive layer to heat and thus, soften the adhesive layer. An electrical resistance heater element is coupled to the peeler bar for providing heat to the peeling surface. The resistance heater element is of a generally low heat output to prevent the adhesive layer from becoming too soft or even actually melting.
The invention, together with additional features and advantages thereof, may be best understood by reference to the following description taken in conjunction with the accompanying illustrative drawings. In these accompanying drawings, like reference numerals designate like parts throughout the figures.